[taz28]

Does anyone have experience of MSD80 ECU failures on 335I's ?

Short history - took the car off road for extended period (6 months) to replace turbo's etc, car was running fine (bar smoking from failing turbos).

Finally got car bolted back together and now have multiple issues:

- 30BB-DME internal failure
- 2aa1-Camshaft Sensor
- 2d33-Pressure sensor
- 29e3-rail pressure

Car starts but runs on 3 cycl, initially assumed its a wiring issue (as i hadn't seen any of these errors prior to starting work) but after lots of checking found nothing.

I then moved on to checking the mosfet's, from the information i found its a simple check, again nothing stood out as incorrect.

I finally admitted defeat and sent the ecu off to a repair company, who have just confirmed yes its failed (with no details) and its £400 to repair.

my questions are:

- has anyone seen complete failures of the ECU before ?
- is £400 a typical repair cost ?

[NoGuru]

Yes, mosfet failures do happen with these ECU's. If you buy them and have a local electronics store solder them it should be pretty cheap to do.

[whyzee125]

Super common issue. IMO just pay the $400–most of the repair places install upgraded ones so it won’t happen again. I wouldn’t risk messing it up as a used DME plus cloning service is about the same plus time and hassle and it still could happen again.

My 07 had a mosfet failure when I purchased it back after selling it a few years before. I sent it off and I think they wanted $300 at the time but turns out someone had already tried to fix it and had damaged the board so I had to get a used one cloned

[Shoooter_j]

You might be able to source it cheaper depending on how much downtime you want to put up with. I got my mosfet replacements from digikey and was lucky to find someone local to do the repair. But since the shop already has your DME and can readily do the repair, might make sense to buy once cry once like whyzee’s saying.

[taz28]

cheers for the reply's / guidance.

Another ouch that hurt in the N54 ownership experience

[Mikasa_e92]

my ECU got flooded, due to blocked drain around the ebox. had all these mosfet errors from the DME, but when i removed it, it was dripping wet.

if its gotta come out anyway, id recommend removing the lower part of the ebox, and cleaning out the drains. mine were full of rotten leaves and shit.

[theoforest]

You can get the upgraded mosfet from Amazon (if they still sell them)
And make a tv repair man install them

Cost me about 150$ total and been 2 years strong